The dynamics of structural deformations of immobilized single light-harvesting complexes
The dynamics of structural deformations of immobilized single light-harvesting complexes
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DOI：
10.1073/pnas.96.20.11271
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发表时间：
1999-09-28
影响因子：
11.1
通讯作者：
Hochstrasser, RM
中科院分区：
文献类型：
--
作者：
Bopp, MA;Sytnik, A;Hochstrasser, RM
单一组件的完整的捕光复合物LH2从嗜酸红球藻绑定到云母表面在300 K，并通过观察它们的荧光偏振光激发后进行检查。复合物通常不是圆柱对称的。它们的作用就像椭圆形吸收体，表明当分子固定在云母上时，LH2晶体中的高对称性不存在。椭圆率和椭圆主轴在秒的时间尺度上波动，表明存在一个移动的构造变形。辅因子的B850环显示出比B800显著更小的不对称性。光漂白强烈依赖于氧的存在。
Single assemblies of the intact light-harvesting complex LH2 from Rhodopseudomonas acidophila were bound to mica surfaces at 300 K and examined by observing their fluorescence after polarized light excitation. The complexes are generally not cylindrically symmetric. They act like elliptic absorbers, indicating that the high symmetry found in crystals of LH2 is not present when the molecules are immobilized on mica. The ellipticity and the principal axes of the ellipses fluctuate on the time scale of seconds, indicating that there is a mobile structural deformation. The B850 ring of cofactors shows significantly less asymmetry than B800. The photobleaching strongly depends on the presence of oxygen.